dplyr notes - R Gapminder
Dave Bridges
4/23/2018
Lets say we want to calculate the average GDP/capita for each continent. lets use subsetting, first lets make sure we have gapminder loaded
Subsetting and calculating means (0-5 mins)
library(gapminder)
#update this based on how Zena taught subsetting
mean(gapminder$gdpPercap)## [1] 7215.327gapminder[gapminder$continent == "Africa",]## # A tibble: 624 x 6
## country continent year lifeExp pop gdpPercap
## <fctr> <fctr> <int> <dbl> <int> <dbl>
## 1 Algeria Africa 1952 43.077 9279525 2449.008
## 2 Algeria Africa 1957 45.685 10270856 3013.976
## 3 Algeria Africa 1962 48.303 11000948 2550.817
## 4 Algeria Africa 1967 51.407 12760499 3246.992
## 5 Algeria Africa 1972 54.518 14760787 4182.664
## 6 Algeria Africa 1977 58.014 17152804 4910.417
## 7 Algeria Africa 1982 61.368 20033753 5745.160
## 8 Algeria Africa 1987 65.799 23254956 5681.359
## 9 Algeria Africa 1992 67.744 26298373 5023.217
## 10 Algeria Africa 1997 69.152 29072015 4797.295
## # ... with 614 more rowsgapminder[gapminder$continent == "Africa",]$gdpPercap## [1] 2449.0082 3013.9760 2550.8169 3246.9918 4182.6638 4910.4168
## [7] 5745.1602 5681.3585 5023.2166 4797.2951 5288.0404 6223.3675
## [13] 3520.6103 3827.9405 4269.2767 5522.7764 5473.2880 3008.6474
## [19] 2756.9537 2430.2083 2627.8457 2277.1409 2773.2873 4797.2313
## [25] 1062.7522 959.6011 949.4991 1035.8314 1085.7969 1029.1613
## [31] 1277.8976 1225.8560 1191.2077 1232.9753 1372.8779 1441.2849
## [37] 851.2411 918.2325 983.6540 1214.7093 2263.6111 3214.8578
## [43] 4551.1421 6205.8839 7954.1116 8647.1423 11003.6051 12569.8518
## [49] 543.2552 617.1835 722.5120 794.8266 854.7360 743.3870
## [55] 807.1986 912.0631 931.7528 946.2950 1037.6452 1217.0330
## [61] 339.2965 379.5646 355.2032 412.9775 464.0995 556.1033
## [67] 559.6032 621.8188 631.6999 463.1151 446.4035 430.0707
## [73] 1172.6677 1313.0481 1399.6074 1508.4531 1684.1465 1783.4329
## [79] 2367.9833 2602.6642 1793.1633 1694.3375 1934.0114 2042.0952
## [85] 1071.3107 1190.8443 1193.0688 1136.0566 1070.0133 1109.3743
## [91] 956.7530 844.8764 747.9055 740.5063 738.6906 706.0165
## [97] 1178.6659 1308.4956 1389.8176 1196.8106 1104.1040 1133.9850
## [103] 797.9081 952.3861 1058.0643 1004.9614 1156.1819 1704.0637
## [109] 1102.9909 1211.1485 1406.6483 1876.0296 1937.5777 1172.6030
## [115] 1267.1001 1315.9808 1246.9074 1173.6182 1075.8116 986.1479
## [121] 780.5423 905.8602 896.3146 861.5932 904.8961 795.7573
## [127] 673.7478 672.7748 457.7192 312.1884 241.1659 277.5519
## [133] 2125.6214 2315.0566 2464.7832 2677.9396 3213.1527 3259.1790
## [139] 4879.5075 4201.1949 4016.2395 3484.1644 3484.0620 3632.5578
## [145] 1388.5947 1500.8959 1728.8694 2052.0505 2378.2011 2517.7365
## [151] 2602.7102 2156.9561 1648.0738 1786.2654 1648.8008 1544.7501
## [157] 2669.5295 2864.9691 3020.9893 3020.0505 3694.2124 3081.7610
## [163] 2879.4681 2880.1026 2377.1562 1895.0170 1908.2609 2082.4816
## [169] 1418.8224 1458.9153 1693.3359 1814.8807 2024.0081 2785.4936
## [175] 3503.7296 3885.4607 3794.7552 4173.1818 4754.6044 5581.1810
## [181] 375.6431 426.0964 582.8420 915.5960 672.4123 958.5668
## [187] 927.8253 966.8968 1132.0550 2814.4808 7703.4959 12154.0897
## [193] 328.9406 344.1619 380.9958 468.7950 514.3242 505.7538
## [199] 524.8758 521.1341 582.8585 913.4708 765.3500 641.3695
## [205] 362.1463 378.9042 419.4564 516.1186 566.2439 556.8084
## [211] 577.8607 573.7413 421.3535 515.8894 530.0535 690.8056
## [217] 4293.4765 4976.1981 6631.4592 8358.7620 11401.9484 21745.5733
## [223] 15113.3619 11864.4084 13522.1575 14722.8419 12521.7139 13206.4845
## [229] 485.2307 520.9267 599.6503 734.7829 756.0868 884.7553
## [235] 835.8096 611.6589 665.6244 653.7302 660.5856 752.7497
## [241] 911.2989 1043.5615 1190.0411 1125.6972 1178.2237 993.2240
## [247] 876.0326 847.0061 925.0602 1005.2458 1111.9846 1327.6089
## [253] 510.1965 576.2670 686.3737 708.7595 741.6662 874.6859
## [259] 857.2504 805.5725 794.3484 869.4498 945.5836 942.6542
## [265] 299.8503 431.7905 522.0344 715.5806 820.2246 764.7260
## [271] 838.1240 736.4154 745.5399 796.6645 575.7047 579.2317
## [277] 853.5409 944.4383 896.9664 1056.7365 1222.3600 1267.6132
## [283] 1348.2258 1361.9369 1341.9217 1360.4850 1287.5147 1463.2493
## [289] 298.8462 335.9971 411.8006 498.6390 496.5816 745.3695
## [295] 797.2631 773.9932 977.4863 1186.1480 1275.1846 1569.3314
## [301] 575.5730 620.9700 634.1952 713.6036 803.0055 640.3224
## [307] 572.1996 506.1139 636.6229 609.1740 531.4824 414.5073
## [313] 2387.5481 3448.2844 6757.0308 18772.7517 21011.4972 21951.2118
## [319] 17364.2754 11770.5898 9640.1385 9467.4461 9534.6775 12057.4993
## [325] 1443.0117 1589.2027 1643.3871 1634.0473 1748.5630 1544.2286
## [331] 1302.8787 1155.4419 1040.6762 986.2959 894.6371 1044.7701
## [337] 369.1651 416.3698 427.9011 495.5148 584.6220 663.2237
## [343] 632.8039 635.5174 563.2000 692.2758 665.4231 759.3499
## [349] 452.3370 490.3822 496.1743 545.0099 581.3689 686.3953
## [355] 618.0141 684.1716 739.0144 790.2580 951.4098 1042.5816
## [361] 743.1159 846.1203 1055.8960 1421.1452 1586.8518 1497.4922
## [367] 1481.1502 1421.6036 1361.3698 1483.1361 1579.0195 1803.1515
## [373] 1967.9557 2034.0380 2529.0675 2475.3876 2575.4842 3710.9830
## [379] 3688.0377 4783.5869 6058.2538 7425.7053 9021.8159 10956.9911
## [385] 1688.2036 1642.0023 1566.3535 1711.0448 1930.1950 2370.6200
## [391] 2702.6204 2755.0470 2948.0473 2982.1019 3258.4956 3820.1752
## [397] 468.5260 495.5868 556.6864 566.6692 724.9178 502.3197
## [403] 462.2114 389.8762 410.8968 472.3461 633.6179 823.6856
## [409] 2423.7804 2621.4481 3173.2156 3793.6948 3746.0809 3876.4860
## [415] 4191.1005 3693.7313 3804.5380 3899.5243 4072.3248 4811.0604
## [421] 761.8794 835.5234 997.7661 1054.3849 954.2092 808.8971
## [427] 909.7221 668.3000 581.1827 580.3052 601.0745 619.6769
## [433] 1077.2819 1100.5926 1150.9275 1014.5141 1698.3888 1981.9518
## [439] 1576.9738 1385.0296 1619.8482 1624.9413 1615.2864 2013.9773
## [445] 2718.8853 2769.4518 3173.7233 4021.1757 5047.6586 4319.8041
## [451] 5267.2194 5303.3775 6101.2558 6071.9414 6316.1652 7670.1226
## [457] 493.3239 540.2894 597.4731 510.9637 590.5807 670.0806
## [463] 881.5706 847.9912 737.0686 589.9445 785.6538 863.0885
## [469] 879.5836 860.7369 1071.5511 1384.8406 1532.9853 1737.5617
## [475] 1890.2181 1516.5255 1428.7778 1339.0760 1353.0924 1598.4351
## [481] 1450.3570 1567.6530 1654.9887 1612.4046 1597.7121 1561.7691
## [487] 1518.4800 1441.7207 1367.8994 1392.3683 1519.6353 1712.4721
## [493] 879.7877 1004.4844 1116.6399 1206.0435 1353.7598 1348.2852
## [499] 1465.0108 1294.4478 1068.6963 574.6482 699.4897 862.5408
## [505] 1135.7498 1258.1474 1369.4883 1284.7332 1254.5761 1450.9925
## [511] 1176.8070 1093.2450 926.9603 930.5964 882.0818 926.1411
## [517] 4725.2955 5487.1042 5768.7297 7114.4780 7765.9626 8028.6514
## [523] 8568.2662 7825.8234 7225.0693 7479.1882 7710.9464 9269.6578
## [529] 1615.9911 1770.3371 1959.5938 1687.9976 1659.6528 2202.9884
## [535] 1895.5441 1507.8192 1492.1970 1632.2108 1993.3983 2602.3950
## [541] 1148.3766 1244.7084 1856.1821 2613.1017 3364.8366 3781.4106
## [547] 3895.3840 3984.8398 3553.0224 3876.7685 4128.1169 4513.4806
## [553] 716.6501 698.5356 722.0038 848.2187 915.9851 962.4923
## [559] 874.2426 831.8221 825.6825 789.1862 899.0742 1107.4822
## [565] 859.8087 925.9083 1067.5348 1477.5968 1649.6602 1532.7770
## [571] 1344.5780 1202.2014 1034.2989 982.2869 886.2206 882.9699
## [577] 1468.4756 1395.2325 1660.3032 1932.3602 2753.2860 3120.8768
## [583] 3560.2332 3810.4193 4332.7202 4876.7986 5722.8957 7092.9230
## [589] 734.7535 774.3711 767.2717 908.9185 950.7359 843.7331
## [595] 682.2662 617.7244 644.1708 816.5591 927.7210 1056.3801
## [601] 1147.3888 1311.9568 1452.7258 1777.0773 1773.4983 1588.6883
## [607] 1408.6786 1213.3151 1210.8846 1071.3538 1071.6139 1271.2116
## [613] 406.8841 518.7643 527.2722 569.7951 799.3622 685.5877
## [619] 788.8550 706.1573 693.4208 792.4500 672.0386 469.7093mean(gapminder[gapminder$continent == "Africa",]$gdpPercap)## [1] 2193.755Now lets do it for the Americas
mean(gapminder[gapminder$continent == "Americas",]$gdpPercap)## [1] 7136.11#now for asia
mean(gapminder[gapminder$continent == "Asia",]$gdpPercap)## [1] 7902.15Here there is lots of repeating yourself, so to do this more reproducibly we are going to use a package called dplyr
#install.packages('dplyr')
library(dplyr)##
## Attaching package: 'dplyr'## The following objects are masked from 'package:stats':
##
## filter, lag## The following objects are masked from 'package:base':
##
## intersect, setdiff, setequal, unionThere are several commands including select, filter and group_by/summarize that we are going to go through today.
Select (5-10 mins)
year_country_gdp <- select(gapminder,year,country,gdpPercap)
gapminder## # A tibble: 1,704 x 6
## country continent year lifeExp pop gdpPercap
## <fctr> <fctr> <int> <dbl> <int> <dbl>
## 1 Afghanistan Asia 1952 28.801 8425333 779.4453
## 2 Afghanistan Asia 1957 30.332 9240934 820.8530
## 3 Afghanistan Asia 1962 31.997 10267083 853.1007
## 4 Afghanistan Asia 1967 34.020 11537966 836.1971
## 5 Afghanistan Asia 1972 36.088 13079460 739.9811
## 6 Afghanistan Asia 1977 38.438 14880372 786.1134
## 7 Afghanistan Asia 1982 39.854 12881816 978.0114
## 8 Afghanistan Asia 1987 40.822 13867957 852.3959
## 9 Afghanistan Asia 1992 41.674 16317921 649.3414
## 10 Afghanistan Asia 1997 41.763 22227415 635.3414
## # ... with 1,694 more rowsyear_country_gdp## # A tibble: 1,704 x 3
## year country gdpPercap
## <int> <fctr> <dbl>
## 1 1952 Afghanistan 779.4453
## 2 1957 Afghanistan 820.8530
## 3 1962 Afghanistan 853.1007
## 4 1967 Afghanistan 836.1971
## 5 1972 Afghanistan 739.9811
## 6 1977 Afghanistan 786.1134
## 7 1982 Afghanistan 978.0114
## 8 1987 Afghanistan 852.3959
## 9 1992 Afghanistan 649.3414
## 10 1997 Afghanistan 635.3414
## # ... with 1,694 more rowsWhat did this do? Select picks out a subset of columns. See image at https://swcarpentry.github.io/r-novice-gapminder/fig/13-dplyr-fig1.png
Image for group_by
Filter (5-10 mins)
Filters can select a subset of rows.
gapminder_euro <- filter(gapminder, continent=="Europe")
#written another way with pipes
gapminder_euro <- gapminder %>% filter(continent=="Europe")Pipes
These allow you to chain several functions together
year_country_gdp_euro <-
gapminder %>%
filter(continent=="Europe") %>%
select(year,country,gdpPercap)Challenge 1 (15-20 mins)
Write a single command (which can span multiple lines and includes pipes) that will produce a dataframe that has the African values for lifeExp, country and year, but not for other Continents. How many rows does your dataframe have and why?Group By with Summarize (20-30 mins)
Now lets look at the combination of group_by and summarize
gapminder## # A tibble: 1,704 x 6
## country continent year lifeExp pop gdpPercap
## <fctr> <fctr> <int> <dbl> <int> <dbl>
## 1 Afghanistan Asia 1952 28.801 8425333 779.4453
## 2 Afghanistan Asia 1957 30.332 9240934 820.8530
## 3 Afghanistan Asia 1962 31.997 10267083 853.1007
## 4 Afghanistan Asia 1967 34.020 11537966 836.1971
## 5 Afghanistan Asia 1972 36.088 13079460 739.9811
## 6 Afghanistan Asia 1977 38.438 14880372 786.1134
## 7 Afghanistan Asia 1982 39.854 12881816 978.0114
## 8 Afghanistan Asia 1987 40.822 13867957 852.3959
## 9 Afghanistan Asia 1992 41.674 16317921 649.3414
## 10 Afghanistan Asia 1997 41.763 22227415 635.3414
## # ... with 1,694 more rowsgapminder %>% group_by(continent)## # A tibble: 1,704 x 6
## # Groups: continent [5]
## country continent year lifeExp pop gdpPercap
## <fctr> <fctr> <int> <dbl> <int> <dbl>
## 1 Afghanistan Asia 1952 28.801 8425333 779.4453
## 2 Afghanistan Asia 1957 30.332 9240934 820.8530
## 3 Afghanistan Asia 1962 31.997 10267083 853.1007
## 4 Afghanistan Asia 1967 34.020 11537966 836.1971
## 5 Afghanistan Asia 1972 36.088 13079460 739.9811
## 6 Afghanistan Asia 1977 38.438 14880372 786.1134
## 7 Afghanistan Asia 1982 39.854 12881816 978.0114
## 8 Afghanistan Asia 1987 40.822 13867957 852.3959
## 9 Afghanistan Asia 1992 41.674 16317921 649.3414
## 10 Afghanistan Asia 1997 41.763 22227415 635.3414
## # ... with 1,694 more rowsLets look at the structure using the str command
str(gapminder)## Classes 'tbl_df', 'tbl' and 'data.frame': 1704 obs. of 6 variables:
## $ country : Factor w/ 142 levels "Afghanistan",..: 1 1 1 1 1 1 1 1 1 1 ...
## $ continent: Factor w/ 5 levels "Africa","Americas",..: 3 3 3 3 3 3 3 3 3 3 ...
## $ year : int 1952 1957 1962 1967 1972 1977 1982 1987 1992 1997 ...
## $ lifeExp : num 28.8 30.3 32 34 36.1 ...
## $ pop : int 8425333 9240934 10267083 11537966 13079460 14880372 12881816 13867957 16317921 22227415 ...
## $ gdpPercap: num 779 821 853 836 740 ...str(gapminder %>% group_by(continent))## Classes 'grouped_df', 'tbl_df', 'tbl' and 'data.frame': 1704 obs. of 6 variables:
## $ country : Factor w/ 142 levels "Afghanistan",..: 1 1 1 1 1 1 1 1 1 1 ...
## $ continent: Factor w/ 5 levels "Africa","Americas",..: 3 3 3 3 3 3 3 3 3 3 ...
## $ year : int 1952 1957 1962 1967 1972 1977 1982 1987 1992 1997 ...
## $ lifeExp : num 28.8 30.3 32 34 36.1 ...
## $ pop : int 8425333 9240934 10267083 11537966 13079460 14880372 12881816 13867957 16317921 22227415 ...
## $ gdpPercap: num 779 821 853 836 740 ...
## - attr(*, "vars")= chr "continent"
## - attr(*, "drop")= logi TRUE
## - attr(*, "indices")=List of 5
## ..$ : int 24 25 26 27 28 29 30 31 32 33 ...
## ..$ : int 48 49 50 51 52 53 54 55 56 57 ...
## ..$ : int 0 1 2 3 4 5 6 7 8 9 ...
## ..$ : int 12 13 14 15 16 17 18 19 20 21 ...
## ..$ : int 60 61 62 63 64 65 66 67 68 69 ...
## - attr(*, "group_sizes")= int 624 300 396 360 24
## - attr(*, "biggest_group_size")= int 624
## - attr(*, "labels")='data.frame': 5 obs. of 1 variable:
## ..$ continent: Factor w/ 5 levels "Africa","Americas",..: 1 2 3 4 5
## ..- attr(*, "vars")= chr "continent"
## ..- attr(*, "drop")= logi TRUEThis is kinda boring but the power is that now things are grouped you can calculate things. Show the image at https://swcarpentry.github.io/r-novice-gapminder/fig/13-dplyr-fig3.png
Image for group_by
gdp_bycontinents <-
gapminder %>%
group_by(continent) %>%
summarize(mean_gdpPercap=mean(gdpPercap))
gdp_bycontinents## # A tibble: 5 x 2
## continent mean_gdpPercap
## <fctr> <dbl>
## 1 Africa 2193.755
## 2 Americas 7136.110
## 3 Asia 7902.150
## 4 Europe 14469.476
## 5 Oceania 18621.609Now lets sort these high to low
gdp_bycontinents <-
gapminder %>%
group_by(continent) %>%
summarize(mean_gdpPercap=mean(gdpPercap)) %>%
arrange(desc(mean_gdpPercap))
gdp_bycontinents## # A tibble: 5 x 2
## continent mean_gdpPercap
## <fctr> <dbl>
## 1 Oceania 18621.609
## 2 Europe 14469.476
## 3 Asia 7902.150
## 4 Americas 7136.110
## 5 Africa 2193.755Now lets do a couple of different calculations
gdp_bycontinents <-
gapminder %>%
group_by(continent) %>%
summarize(mean_gdpPercap=mean(gdpPercap),
max_gdpPercap=max(gdpPercap),
min_gdpPercap=min(gdpPercap))
gdp_bycontinents## # A tibble: 5 x 4
## continent mean_gdpPercap max_gdpPercap min_gdpPercap
## <fctr> <dbl> <dbl> <dbl>
## 1 Africa 2193.755 21951.21 241.1659
## 2 Americas 7136.110 42951.65 1201.6372
## 3 Asia 7902.150 113523.13 331.0000
## 4 Europe 14469.476 49357.19 973.5332
## 5 Oceania 18621.609 34435.37 10039.5956Group By and Summarize Challenge (30-35)
Calculate the average life expectancy per country. Which has the longest average life expectancy and which has the shortest average life expectancy?Multiple variables (35-40)
#lets group by multiple variables, here lets now incude year and contienent
gdp_bycontinents_years <-
gapminder %>%
group_by(continent,year) %>%
summarize(mean_gdpPercap=mean(gdpPercap)) %>%
arrange(desc(mean_gdpPercap))
gdp_bycontinents_years## # A tibble: 60 x 3
## # Groups: continent [5]
## continent year mean_gdpPercap
## <fctr> <int> <dbl>
## 1 Oceania 2007 29810.19
## 2 Oceania 2002 26938.78
## 3 Europe 2007 25054.48
## 4 Oceania 1997 24024.18
## 5 Europe 2002 21711.73
## 6 Oceania 1992 20894.05
## 7 Oceania 1987 20448.04
## 8 Europe 1997 19076.78
## 9 Oceania 1982 18554.71
## 10 Oceania 1977 17283.96
## # ... with 50 more rowsMutate (40-45 mins)
Mutate adds a new column
gdp_bycontinents <-
gapminder %>%
group_by(continent) %>%
summarize(mean_gdpPercap=mean(gdpPercap),
max_gdpPercap=max(gdpPercap),
min_gdpPercap=min(gdpPercap))
gdp_bycontinents## # A tibble: 5 x 4
## continent mean_gdpPercap max_gdpPercap min_gdpPercap
## <fctr> <dbl> <dbl> <dbl>
## 1 Africa 2193.755 21951.21 241.1659
## 2 Americas 7136.110 42951.65 1201.6372
## 3 Asia 7902.150 113523.13 331.0000
## 4 Europe 14469.476 49357.19 973.5332
## 5 Oceania 18621.609 34435.37 10039.5956gdp_bycontinents <-
gapminder %>%
group_by(continent) %>%
summarize(mean_gdpPercap=mean(gdpPercap),
max_gdpPercap=max(gdpPercap),
min_gdpPercap=min(gdpPercap)) %>%
mutate(diff_gdpPercap=max_gdpPercap-min_gdpPercap)
gdp_bycontinents## # A tibble: 5 x 5
## continent mean_gdpPercap max_gdpPercap min_gdpPercap diff_gdpPercap
## <fctr> <dbl> <dbl> <dbl> <dbl>
## 1 Africa 2193.755 21951.21 241.1659 21710.05
## 2 Americas 7136.110 42951.65 1201.6372 41750.02
## 3 Asia 7902.150 113523.13 331.0000 113192.13
## 4 Europe 14469.476 49357.19 973.5332 48383.66
## 5 Oceania 18621.609 34435.37 10039.5956 24395.77Piping to GGPlot (45-50 mins)
library(ggplot2)
gapminder %>%
group_by(year,continent) %>%
summarize(mean_life_exp = mean(lifeExp)) %>%
# Make the plot
ggplot(aes(x = year, y = mean_life_exp)) +
geom_line() +
facet_wrap(~continent)
Final Challenge (55-60 mins)
Calculate the average life expectancy in 2002 of 2 randomly selected countries for each continent. Then arrange the continent names in reverse order. Hint: Use the dplyr functions arrange() and sample_n(), they have similar syntax to other dplyr functions.